Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.
Gaja Cvejić Vidali
Hematology department, University Medical Center Ljubljana, Ljubljana, Slovenia
gaja.cvejic.vidali@kclj.si

Main Body of the Abstract
Background Carpal tunnel syndrome (CTS) is an early manifestation of systemic amlyoidosis. In transthyretin amyloidosis (ATTR) is established in diagnostic algorithms; its incidence in light chain (AL) amyloidosis is approximately 9%. We conducted a prospective analysis with an aim of determining the incidence of AL amyloidosis in patients with CTS and monoclonal immunoglobulin (mIg).
Methods From March 2019 to the end of the year 2022, pateints referred to the plastic surgery outpatients clinic or electro-neurophysiology unit were invited to participate in the study. Serum and urin protein electrophoresis with a free light chain (FLC) assay were analyzed, together with parameters of organ failure and clinical symptoms survey. Patients with proven mIg were invited to proceed with a biopsy of carpal tunnel's ligamentum transversum in the case of surgical release or an abdominal fat biopsy in the case of conservative management of CTS.
Results 94 patiens with CTS participated in the study. mIg was found in 8 patients (9 %), half of them agreed with further diagnostics. First patient's IgG lambda disapeared on first follow up and due to lack of symptoms we did not proceed with biopsy. Second patient with IgG lambda, CTS, polyneuropathy and increased NT-proBNP underwent abdominal fat biopsy without evidence of amyloid deposition. The abdominal fat biopsy of a third patient with IgM kappa and axonal polyneuropathy was negative for amyloid depositions and on further follow ups, the PNP was contibuted to inherited CMT2 neuropathy. Fourth patient had a trace of IgG kappa and biopsy of ligamentum transversum revealed transthyretin amyloidosis with coincidental mIg.
Conclusion In this prospective analysis, 9% of patients with Cts were found to have mIg. No evidence of AL amyloidosis was found on histological specimens. One patient was diagnosed with early-stage ATTRwt.

**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Gaja Cvejić Vidali
Hematology department, University Medical Center Ljubljana, Ljubljana, Slovenia
gaja.cvejic.vidali@kclj.si

**Main Body of the Abstract**
**_Background_** Carpal tunnel syndrome (CTS) is an early manifestation of systemic amlyoidosis. In transthyretin amyloidosis (ATTR) is established in diagnostic algorithms; its incidence in light chain (AL) amyloidosis is approximately 9%. We conducted a prospective analysis with an aim of determining the incidence of AL amyloidosis in patients with CTS and monoclonal immunoglobulin (mIg).
**_Methods_** From March 2019 to the end of the year 2022, pateints referred to the plastic surgery outpatients clinic or electro-neurophysiology unit were invited to participate in the study. Serum and urin protein electrophoresis with a free light chain (FLC) assay were analyzed, together with parameters of organ failure and clinical symptoms survey. Patients with proven mIg were invited to proceed with a biopsy of carpal tunnel's ligamentum transversum in the case of surgical release or an abdominal fat biopsy in the case of conservative management of CTS.
**_Results_** 94 patiens with CTS participated in the study. mIg was found in 8 patients (9 %), half of them agreed with further diagnostics. First patient's IgG lambda disapeared on first follow up and due to lack of symptoms we did not proceed with biopsy. Second patient with IgG lambda, CTS, polyneuropathy and increased NT-proBNP underwent abdominal fat biopsy without evidence of amyloid deposition. The abdominal fat biopsy of a third patient with IgM kappa and axonal polyneuropathy was negative for amyloid depositions and on further follow ups, the PNP was contibuted to inherited CMT2 neuropathy. Fourth patient had a trace of IgG kappa and biopsy of ligamentum transversum revealed transthyretin amyloidosis with coincidental mIg.
**_Conclusion_** In this prospective analysis, 9% of patients with Cts were found to have mIg. No evidence of AL amyloidosis was found on histological specimens. One patient was diagnosed with early-stage ATTRwt.

The incidence of AL amyloidosis in patients with carpal tunnel syndrome PA59 (#179)

We invite you to attend the XIX International Symposium on Amyloidosis to be held in Rochester, MN.

This symposium is organized as a hybrid meeting (with the focus on in-person) held from Sunday, May 26 through Thursday, May 30, 2024.

Together with the ISA Board and members of Mayo Clinic, a very attractive scientific hybrid program is being planned. The program will cover a variety of types of systemic amyloidosis: ATTR (hereditary and wild-type), AL (light-chain), AA and less frequent forms. There will be key lectures, specific symposia including those company sponsored, oral presentations and poster sessions of accepted abstracts.

COURSE DESCRIPTION
This program will provide a comprehensive review of state-of-the-art education in systemic amyloidosis: basic science, pathophysiology, diagnosis, current and emerging treatments. Scientific presentations will include competitive oral and poster abstracts. The rapid evolution of scientific discovery and expanding treatment options has created tremendous interest in the field and this meeting will fill and important gap in educating scientists and clinicians.